Survey of nitrate and nitrite contents of vegetables grown in Korea

Abstract

A scientific basis for the evaluation of the risk to public health arising from excessive dietary intake of nitrate in Korea is provided. The nitrate () and nitrite () contents of various vegetables (Chinese cabbage, radish, lettuce, spinach, soybean sprouts, onion, pumpkin, green onion, cucumber, potato, carrot, garlic, green pepper, cabbage and Allium tuberosum Roth known as Crown daisy) are reported. Six hundred samples of 15 vegetables cultivated during different seasons were analysed for nitrate and nitrite by ion chromatography and ultraviolet spectrophotometry, respectively. No significant variance in nitrate levels was found for most vegetables cultivated during the summer and winter harvests. The mean nitrates level was higher in A. tuberosum Roth (5150 mg kg(-1)) and spinach (4259 mg kg(-1)), intermediate in radish (1878 mg kg(-1)) and Chinese cabbage (1740 mg kg(-1)), and lower in onion (23 mg kg(-1)), soybean sprouts (56 mg kg(-1)) and green pepper (76 mg kg(-1)) compared with those in other vegetables. The average nitrite contents in various vegetables were about 0.6 mg kg(-1), and the values were not significantly different among most vegetables. It was observed that nitrate contents in vegetables varied depending on the type of vegetables and were similar to those in vegetables grown in other countries. From the results of our studies and other information from foreign sources, it can be concluded that it is not necessary to establish limits of nitrates contents of vegetables cultivated in Korea due to the co-presence of beneficial elements such as ascorbic acid and alpha-tocopherol which are known to inhibit the formation of nitrosamine.

Average daily nitrate and nitrite intake in the Belgian population older than 15 years

“…Nitrate concentrations of most vegetables 312 analyzed during this study fall within the wide range of values reported before by 313 Dejonckheere et al, 1996) However, other vegetables contained higher nitrate concentrations 314 (e.g. turnip) and for others no concentrations have been reported so far (rhubarb, courgette) 315 (Belitz H-D et al 1999;Chung et al 2003;Penttilä PL 1995;Petersen and Stoltze 1999;316 Tamme et al 2006). 317 with the highest concentrations in fresh, then frozen and the lowest in vegetables preserved in 319 can or glass.…”

Extraction of NOx and Determination of Nitrate by Acid Reduction in Water, Soil, Excreta, Feed, Vegetables and Plant Materials

“…However, nitrite levels exceeding about 0.3 ppm as N in top soil is considered toxic for growing plants (Singh et al, 2007). Vegetables contribute dominantly, 60 to 90 % or above, to dietary nitrate intake in humans followed by water (Schuddeboom, 1993;Chiroma et al, 2007;Lukassowitz, 2005 (Anjana et al, 2007;Chiroma et al, 2007;Chung et al, 2003;Schuddeboom, 1993). Nitrite nitrogen in the vegetables has been either undetectable (Schuster and Lee, 1987) or in the range of 0.06 to 1.2 ppm N (Rao and Puttanna, 2000;Chung et al, 2003;Lyons et al, 2006).…”

“…Vegetables contribute dominantly, 60 to 90 % or above, to dietary nitrate intake in humans followed by water (Schuddeboom, 1993;Chiroma et al, 2007;Lukassowitz, 2005 (Anjana et al, 2007;Chiroma et al, 2007;Chung et al, 2003;Schuddeboom, 1993). Nitrite nitrogen in the vegetables has been either undetectable (Schuster and Lee, 1987) or in the range of 0.06 to 1.2 ppm N (Rao and Puttanna, 2000;Chung et al, 2003;Lyons et al, 2006). The regulatory levels of nitrate in vegetables vary with respect to type of vegetable and from country to country with range from about 55 to 1100 ppm N while nitrite levels are usually < 3 ppm N (Schuddeboom, 1993).…”

Spectrophotometric Assessment of the Differences Between Total Nitrate/Nitrite Contents in Peel and Flesh of Cucumbers

“…The minimum nitrate content of 1 mg kg −1 was found in Korea during the summer period (Chung et al 2003). The nitrite contents found in cucumbers were generally low and in most cases did not exceed 1 mg kg −1…”